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Answer the questions below with reference to the compounds X, Y and Z in the following reaction scheme - Leaving Cert Chemistry - Question 8 - 2013
Question 8
Answer the questions below with reference to the compounds X, Y and Z in the following reaction scheme. Name X, Y and Z. Which one of the compounds, X, Y or Z, con... show full transcript
Worked Solution & Example Answer:Answer the questions below with reference to the compounds X, Y and Z in the following reaction scheme - Leaving Cert Chemistry - Question 8 - 2013
Step 1
Step 2
Which one of the compounds, X, Y or Z, contains only one planar carbon atom? Draw the full structural formula of this compound and indicate clearly the carbon atom that is in planar geometry.
Answer
The compound that contains only one planar carbon atom is Y (ethanal).
The structural formula of ethanal is:
H O
\ ||
C
/ \
H H
The planar carbon atom is the one that is double-bonded to the oxygen.
Step 3
Step 4
Describe how you would test product Y with Fehling's reagent.
Answer
To test product Y (ethanal) with Fehling's reagent:
- Add a little of Y to a test tube.
- Include Fehling's solution.
- Heat gently.
A red precipitate of copper(I) oxide (cuprous oxide, Cu2O) will form, indicating a positive result.
Step 5
Draw a clearly labelled diagram to show how you would obtain a sample of compound Z from compound X by reaction B in a school laboratory.
Answer
The diagram for obtaining compound Z (ethene) from compound X (ethanol) is as follows:
Glass wool
|
Aluminium oxide
|
Delivery tube
/ \
------- / \ -------
| X | | Y |
------- \ / -------
|
Water
| |
Trough
Label A: Condenser; Label B: Test tube; Label C: Water trough. Note that both left and right assembly must be correctly labelled.